This invention relates to thermostats for electrical appliances, and particularly thermostats having a positive off position.
Thermostats are used in a variety of electrically heated appliances, such as grills and griddles, frypans, waffle irons, cooking vessels, irons, and others. The function of the thermostat is to control the operation of an electrical heating element of the appliance in order to maintain a selected temperature. In order to accomplish this function in a highly satisfactory manner, the thermostat would most desirably have all of the following features and characteristics. It should be simple, inexpensive and reliable, and this is best accomplished through constructing the thermostat from a minimum number of parts which are easily assembled. The thermostat should be accurate, and accuracy is enhanced by good calibration characteristics. The thermostat should be compact, so as not to unduly increase the size and weight of the appliance. The thermostat should have a positive off position, i.e., a position in which the heating element of the appliance cannot be turned on by the thermostat regardless of the ambient temperature, thus eliminating the need for a separate off/on switch.
While various prior art thermostats have adequately met some of these criteria, none have achieved all of them, and there still remains a need for a better thermostat.